Direct-print silver halide emulsions containing a halogen acceptor and an amine compound as a stabilizer



United States Patent 3,486,901 DIRECT-PRINT SILVER HALIDE EMULSIONSCONTAINING A HALOGEN ACCEPTOR AND AN AMINE COMPOUND AS A STABILIZERRichard Warren Karlson, Rochester, N.Y., assiguor to Eastman KodakCompany, Rochester, N.Y., a corporation of New Jersey No Drawing. FiledOct. 21, 1966, Ser. No. 588,286 Int. Cl. G03c l /06, 1/28 U.S. CI. 969421 Claims ABSTRACT OF THE DISCLOSURE This invention relates tophotographic direct-print, silver halide emulsions comprising anitrogen-containing halogen acceptor and a secondary, tertiary orquaternized amine compound as a stabilizer. In one aspect, cyanine andmerocyanine dyes are used in combination with the amine stabilizers indirect-print emulsions to provide improved image properties.

The present invention relates to photography. In one aspect, thisinvention relates to direct-print, photographic silver halide emulsions.In another aspect, this invention relates to photographic elementscomprising a support and at least one direct-print, silver halide layercoated thereon.

Radiation sensitive papers adapted for light recording, e.g.,oscillographic recording, are well known. Typical of such papers are thedeveloping-out and print-out type. The develop-out type requires theexposed material to be chemically developed, fixed and washed to providea useful image. The print-out type of material develops on exposure tolight. The print-out type is generally much slower than thedeveloping-out type, and the images are unstable and have a short life.

Another type of radiation-sensitive material, especially suitable forrecording actinic radiation, comprises a silver halide emulsion layerwhich, when exposed to a high intensity source of radiation, forms alatent image which can then be developed by exposure to a second sourceof radiation of lower intensity. Such direct-writing or direct-printingemulsions are faster than print-out emulsions and require no chemicaldevelopment. Howevery, many of the recording papers of this latter typehave low image stability with respect to time; the background areas tendto build up to obscure the images upon subsequent exposure to light andthe image areas tend to fade resulting in low image discrimination.

It is, therefore, an object of this invention to provide a new class oflight-developable direct-print, radiationsensitive silver halideemulsions.

It is another object of this invention to provide novel photographiclight-developable silver halide emulsions that are characterized ashaving high density differential between the high density radiationexposed areas and the unexposed areas upon subsequent photodevelopment.

It is another object of this invention to provide new photodevelopable,direct-print, silver halide emulsions that have a high resistance todensity loss in the image areas and a high resistance to densitybuild-up in the background areas of the photodeveloped emulsion.

It is another object of this invention to provide novel photographiclight-developable, direct-print silver halide emulsions that can bechemically developed and fixed before or after photodevelopment to makearchival-quality records.

It is another object of this invention to provide a means formaintaining a high image density and a low background density in aphotodeveloped direct-print element.

3,486,901 Patented Dec. 30, 1969 Other objects of this invention willbecome apparent from the description and claims. These and other objectsof the invention are accomplished by a novel, direct-print,radiation-sensitive, silver halide emulsion comprising anitrogen-containing halogen acceptorand an amine stabilizer. The novelcomposition provides an unexpected improvement in stabilizing the ratioof image density to background density in a photodeveloped direct-printelement during subsequent exposure to room light. The direct-printemulsion comprising the nitrogen-containing halogen acceptor without theamine stabilizer has a relatively poor image stability as compared tothe novel composition of this invention. Moreover, the amine stabilizersof this invention are not eifective halogen acceptors; an emulsioncomprising the amine stabilizer without the nitrogencontaining halogenacceptor provides relatively poor direct-print image quality. Therefore,it is quite unexpected that a direct-print emulsion comprising the aminestabilizer and the nitrogen-containing halogen acceptor provide anappreciable improvement in direct-print quality.

An additional improvement in image quality of directprint emulsion isobserved when the composition of this invention further comprises acyanine or merocyanine dye. The ratio of image density to backgrounddensity is further improved with respect to subsequent light exposureafter photodevelopment. The difliculties in stabilizing images ofdirect-print films is apparent from an inspection of the priorliterature. Thioethers have been used during theprecipitation step toimprove image stability as in McBride, US. Patent No. 3,271,157 issuedSept. 6, 1966. The use of zinc and cadmium nitrate for this purpose isdescribed in German Patent No. 1,177,064. The alkyl amines, as used inthe present invention, provide a novel approach to this problem andexhibit an unexpected appreciable improvemnt in maintaining good imagediscrimination in direct-print elements.

The amine stabilizers utilized in the direct-print emulsions containingthe nitrogen containing halogen acceptors of this invention arecharacterized as having at least one alkyl, hydroxyalkyl or carboxyalkylradical attached to the nitrogen atom. Moreover, the amine stabilizersare not eflicient halogen acceptors when used alone in directprintemulsions. The amine stabilizers of this invention are generallyrepresented by the formulae:

R2 R R2 2 R NR 1 /NR1N 63 (N) R R R*)... 1 X )m 1 A wherein R is analkylene radical, R R R and -R can each be a hydrogen atom, a hydroxyradical, an aryl radical, i.e., including those of the naphthyl andphenyl series and such common substituents as alkyl groups, halogenatoms, and the like, a earboxyalkyl radical or a hydroxyalkyl radicalprovided that at least one of the substituents R R R and R of eachcompound is an alkyl radical, carboxyalkyl radical or hydroxyalkylradical; m is a positive integer of l to 2, X is an anion necessary toform a quaternary salt and A is the required number of atoms to form a 5to 6 member saturated ring.

The nitrogen atoms in said ring have carbon atoms adjacent thereto inthe ring to form groups such as morpholine, piperazine, piperidine,thiamorpholine and etc. Moreover, in the preferred amine stabilizers ofthis invention when the ring contains only 2 heteroatoms they are parato one another.

The saturated ring includes rings containing alkyl radicals, hydroxyradicals, hydroxyalkyl radicals and carboxyalkyl radicals and etc.substituted thereon. It will be understood that compounds containingresonant structures, e.g., a

X XH ll J;

group, in the ring provide unsaturation and are not intended to beincluded within the saturated ring referred to in the specification andclaims.

The salts of the amine stabilizer, such as the alkali metal salts whencarboxy groups are present as well as the above-defined quaternaryamines are effective stabilizers and are also included within thedefinition of the amine stabilizer.

The amine stabilizer is utilized in concentrations of about to about 100g./mole of silver halide in the composition, the concentrations beingdependent, of course, on the type of amine used and the effect desiredin the composition. In the preferred embodiment the amine is in thesecondary, tertiary or quaternary form and is utilized in concentrationsof about to about 70 g./mole of silver halide in the composition.Typical examples of suitable amine stabilizers used in the direct-printemulsions of this invention are triethyl amine, ethyl amino ethanol,diethyl amino ethanol, morpholine, l-thiamorpholine-4-ethanol, ethylenedinitrilo tetraacetic acid disodium salt, tetraethylammonium hydroxide,N-ethyl morpholine, N-methyl piperazine, N-ethyl piperadine, diethylethylene diamine, and etc.

Typical nitrogen containing halogen acceptors which can be utilized inthe emulsions of this invention can be represented by the followingformulae:

wherein R R R R R R R R R and R can each be hydrogen atoms, alkylradicals, aryl radicals, including substituted alkyl and aryl radicals,or acyl radicalse.g.,

wherein R is a hydrogen atom, an alkyl radical or an aryl radical-and Rand R can also be amino radicals represented by the formula and iminoradicals represented by the formula i N-R" wherein R and R can be ahydrogen atom, an alkyl group, an aryl group, including substitutedalkyl and aryl groups, or acyl radicals; X can be oxygen or sulfur, Ecan be an oxygen atom, a sulfur atom, a selenium atom, or an iminoradical; and Q and Z can be the necessary atoms to complete aheterocyclic nucleus generally having 5 to 6 members. Q and Z typicallyare the necessary atoms to complete such moieties as triazole-thiol, amercaptoimidazole, an imidazolidine-thione, a triazine-thiol, athiobarbituric acid, or thiouracil, a urazole including a thiourazoleand the like heterocyclic moieties.

With respect to the above formulas of nitrogen-containing halogenacceptors: the aryl radical substituents are those of the naphthyl andphenyl series, and include such common substituents as alkyl groups,halogen atoms, acyl radicals and the like; the alkyl radicalsubstituents typically can contain 1 to 20 carbon atoms and moregenerally 1 to 8 carbon atoms, and can be substituted with such radicalsas aryl radicals, halogen atoms, acyl radicals, and the like.

Examples of specific nitrogen-containing halogen acceptors which can beeffectively used with the amine stabilizers of this invention are setout below.

l,3-dimethyl-Z-imidazolidinethione Z-imidazolidinethionel-phenyl-5-mercaptotetrazole Thiosemicarbazide Tetramethylthioureap-Dimethylaminobenzaldehyde-thiosemicarbazone l-isopentyl-Z-thiourea l-Z-diethylaminoethyl l ,2,5,6-tetrahydro- 1,3,5 -triazine-4-thiol1,2-bis( l,2,5,6-tetrahydro-l,3,5-triazine-4-thiol)ethanel-phenyl-Z-thiourea l,3-diphenyl-2-thiourea 4-thiobarbituric acid2-thiouracil l-acetyLZ-thiourea 1,3-dibenzyl-2-thioureal,1-diphenyl-2-thiourea l-ethyl- 1- or-naphthyl) -2-thiourea2-mercaptoimidazole 1-phenyl-2-imidazolidinethione4,5-diphenyl-4-irnidazolidine-2-thione 1-methyl-2-mercaptoimidazolel-n-butyl-l,2,5,6-tetrahydro-l,3,5-triazine-4-thiol Thioureal-methyl-Z-imidazolidinethione D-mannose thiosemicarbazoneMorpholino-Z-propane thiosemicarbazone D-galactose thiosemicarbazoneUrazole 3-thiourazole 3,5-dithiourazole 3,5-dithiourazole hydrazine salt4-aminourazole hydrazine salt Urazole sodium salt 4-( 1-naphthyl)urazole4-ethylurazole l-phenylurazole 4-pheny1urazole l-butylurazolel-octylurazole 4-butyl-3,5-dithiourazole 1,4-diphenylurazole1,4-dibutylurazole 1,4-dibutyl-3,S-dithiourazole1,4-diphenyl-3,S-dithiourazole 1-ethyl-4-phenylurazolel-ethyl-4-phenyl-3,S-dithiourazole 3-thio-5-iminourazole 5-selenourazoleHydrazine Phenylhydrazine hydrochloride 2,5-dichlorophenyl hydrazinep-Tolylhydrazine hydrochloride a-Naphthylhydrazineot-Benzyl-a-phenylhydrazine p-Toluene sulfonyl hydrazine HexylhydrazineThe concentrations of the described nitrogen-containing halogenacceptors utilized in the silver halide emulsions of the invention canbe widely varied in accordance with usual practice. Generally, about .1to mole percent, and preferably about 1 to 50 mole percent, based on thesilver halide in the emulsion of the nitrogen-containing halogenacceptor is utilized.

A wide variety of light-developable, direct-print, photographic silverhalide emulsions can be utilized in the invcntion, such being well knownto those skilled in the art. Suitable silver halides include silverchloride, silver bromide, silver bromoiodide, silver chloroiodide, andsilver chlorobromoiodide. The preferred emulsions are those wherein thehalide of the silver halide is predominantly bromide. For a descriptionof suitable emulsions, reference is made to Davey et al., U.S. PatentNo. 2,592,250, issued Apr. 8, 1952; Glafkides, Photographic Chemistry,vol. 1, pp. 312, Fountain Press, London; and in McBride, U.S. Patent No.3,271,157, issued Sept. 6, 1966, wherein is disclosed the preparation ofsilver halide emulsions with organic thioether silver halide solventspresent during the grain growth of the silver halide. In the McBridepatent is taught the addition of the thioether silver halide solvent tothe colloidal material in which the silver halide is precipitated,during the precipitation of the silver halide or to the silver halideprior to or during the ripening of the silver halide. Typical of suchthioethers are 3,6-dithia-1,8-octanediol, 1,10 -dithia- 4,7,13,16-tetraoxacyclooctadecane, 7,10-diaza-1,16-dicar boxamido-3,.4-dithia-hexadecane-6,1l-dione, and 1,17- di- (N-ethylcarbamyl)-6,12-dithia-9-oxaheptadecane. The amount of thioether utilized toprepare the silver halide emulsions can be widely varied although about.1 to 25 g. of thioether per mole of silver halide is generallyutilized. The present silver halide emulsions generally have an averagegrain size of about .1 to microns, and more generally about .5 to 1micron.

The so-called internal image emulsions can be used in the invention,such having silver halide grains wherein a predominant amount of thesensitivity is internal to the grains. Such internal image emulsions arethose which, when measured according to normal photographic techniquesby coating 3. test portion of the emulsion on a transparent support,exposing to a light intensity scale having a fixed time between 1 10 and1 second, bleaching 5 minutes in a 0.3% potassium ferricyanide solutionat 65 F. and developing for about 5 minutes at 65 F. in Developer Bbelow (an internal-type developer) have a sensitivity, measured at adensity of 0.1 above fog, greater than the sensitivity of an identicaltest portion which has been exposed in the same way and develop-ed for 6minutes at 68 F. in Developer A below (a surface-type developer).

DEVELOPER A G. N-methyl-p-aminophenol sulfate 0.31 Sodium sulfite,desiccated 39.6 Hydroquinone 6.0 Sodium carbonate, desiccated 18.7Potassium bromide 0.86 Citric acid 0 .68 Potassium metabisulfite 1.5Water to make 1 liter.

DEVELOPER B N-methyl-p-aminophenol sulfate 2.0 Sodium sulfite,desiccated 90.0 Hydroquinone 8.0 Sodium carbonate, monohydrate 52.5Potassium bromide 5.0 Sodium thiosulfate 10.0

Water to make 1 liter.

Various colloids can be used as vehicles or binding agents in preparingthe silver halide emulsions of this invention. Satisfactory colloidswhich can be used for this purpose include any of the hydrophiliccolloids generally employed in the photographic field, including, forexam ple, gelatin, colloidal albumin, polysaccharides, cellulosederivatives, synthetic resins such as polyvinyl compounds, includingpolyvinyl alcohol derivatives acrylamide polymers and the like. Inaddition to the hydrophilic colloids, the vehicle or binding agent cancontain hydrophobic colloids such as dispersed polymerized vinylcompounds, particularly those which increase the dimensional stabilityof photographic materials. Suitable compounds of this type includeWater-insoluble polymers of alkyl acrylates or methacrylates, acrylicacid, sulfoalkyl acrylates or methacrylates and the like.

Although silver halide emulsions are generally made with an equivalentor slight excess of halide ion present, I have found it desirable to addadditional water-soluble iodide to the silver halide emulsion after itsprecipitation but before it is coated. More generally, about .1 to 50mole percent, and preferably about 1 to 10 mole percent of water-solubleiodide based on the silver halide in the emulsion is used. Illustrativewater-soluble iodides include ammonium, calcium, lithium, magnesium,potassium, or sodium iodide.

Lead ions are used in the precipitation or formation of the silverhalide of the emulsions of the invention. Watersoluble lead salts aresuitably added with the water-solule silver salt to an appropriatewater-soluble halide to precipitate the lead-silver halide of thepresent emulsions. Typical suitable water-soluble lead or plumbous saltsinclude lead acetate, lead nitrate, lead cyanide, and the like. Theamount of lead utilized in the silver halide of the emulsions of theinvention suitably ranges from about .01 to 5 mole percent based on thesilver halide. The presence of a water-soluble lead salt during thesilver halide formation or grain growth when preparing thelight-developable, direct-print emulsions of the invention is to bedistinguished from the addition of a watersoluble lead salt shortlyprior to coating and after the silver halide grains have been formed.

The emulsion can be hardened with any suitable hardener for gelatin.Suitable hardeners include formaldehyde polyfunctional hardeners havingtwo or more reactive groups which will react with the gelatin, e.g.,halogensubstituted aliphatic acids such as mucobromic acid as describedin White, U.S. Patent No. 2,080,019 (issued May 11, 1937); compoundshaving a plurality of acid anhydride groups such as7,8-diphenyl-bicy-clo(2,2,2)-7- octene-2,3,5,6-tetracarboxylicdianhydride, or a dicarboxylic or disulfonic acid chloride such asterephthaloyl chloride or naphthalene-1,S-disulfonyl chloride asdescribed in Allen and Carrol, U.S. Patents 2,725,294 and 2,725,- 295(boih issued Nov. 29, 1955); a cyclic 1,2-diketone such ascyclopentane-1,2-dione as described in Allen and Byers, U.S. Patent2,725,305 (issued Nov. 29, 1955); a bisester of methane-sulfonic acid,such as 1,2-di(methane, sulfonoxy)ethane as described in Allen andLaakso, U.S. Patent No. 2,726,162 (issued Dec. 6, 1955);1,3-dihydroxymethyl-benzimadazol-2-one as described in July, Knott andPollak, U.S. Patent No. 2,732,316 (issued J an. 24, 1956); aglutaraldehyde or a sodium bisulfite derivative thereof, such as3-methyl-glutaraldehyde bis-sodium bisulfite; a bisaziridinecarboxamide, such as trimethylene bis(1-aziridine carboxamide) asdescribed in Allen and Webster, U.S. Patent No. 2,950,197 (issued Aug.23, 1960); or 2,3-dihydroxy dioxane as described in Jetfreys, U.S.Patent No. 2,870,013 (issued Jan. 20, 1959); or with oxy plant gums asdescribed in Jeflreys et al., U.S. Patent No. 3,062,652 (issued Nov. 6,1962).

The emulsions of the invention can contain a coating aid, such assaponin; a lauryl or oleoyl monoether of polyethylene glycol asdescribed in Knox and Davis, U.S. Patent No. 2,831,766 (issued Apr. 22,1958); a salt of a sulfated and alkylated polyethylene glycol ether asdescribed in Knox and Davis, U.S. Patent No. 2,719,087 (issued Sept. 27,1955); an acylated alkyl taurine, such as the sodium salt ofN-oleoyl-N-methyltaurine as described in Knox, Twardokus and Davis, U.S.Patent No. 2,739,891 (issued Mar. 27, 1956); the reaction product of adianhydride of tetracarboxybutane with an alcohol or an aliphatic aminecontaining from 8 to 18 carbon atoms which is treated with a base, forexample, the sodium. salt of the monoester of tetracarboxybutane asdescribed in Knox, Stenberg, and Wilson, U.S. Patent No. 2,843,487(issued July 15, 1958); a Water-soluble maleopimarate or a mixture of aWater-soluble rnaleopimarate and a substituted glutamate salt asdescribed it. Knox and Fowler, US. Patent No. 2,823,123 (issued Feb. 11,1958); an alkaline metal salt of a substituted amino acid, such asdisodiurn N-(carbon-p-tert.octylphenoxypentaethoxy)glutamate, or asulfosuccinarnate, such as tetrasodiurnN-(1,2-dicarboxyethyl)-N-octadecyl sulfosuccinamate, o-r N-lauryldisodium sultosuccinamate.

The above-described emulsions of the invention can be coated on a widevariety of supports in accordance with usual practice. Typical supportsfor photographic elements of the invention include glass, metals, paper,polyethylene-coated paper, polypropylene-coated paper, cellulose nitratefilm, cellulose acetate film, polyvinyl acetal film, polystyrene film,polyethylene-terephthalate film and related films of resinous materialsand others.

Sensitizing dyes have been found to provide increased stability whenadded to direct-print, silver halide emulsions comprising the aminestabilizers and nitrogen-containing halogen acceptors of this invention.The dyes provide an additional improvement in stabilizing the ratio ofimage density to background density upon subsequent exposure toradiation.

Particularly useful dyes in the direct-print composition to provide astabilizing effect are the cyanine and merocyanine dyes. The merocyaninedyes have the formula:

R -l l(Oll=CH)m b(=C-O)n: =x

| l R21 322 Y wherein X can be a sulfur or a selenium atom; R R R and Rare each an alkyl radical (e.g., methyl, ethyl, carbethoxymethyl,carboxymethyl, benzyl (phenylmethyl), fl-sulfoethyl, butyl, etc.), anaryl radical, such as phenyl, tolyl, etc., and R R and R can also be ahydrogen atom; Y is an oxygen atom, a sulfur atom, a selenium atom,

wherein R can be any of the substituents of R and wherein R can be anyof the substituents of R 112 is a positive integer of 1 or 2 andpreferably 1; n is a positive integer of 1 or 2; when m=l and 11:1 or 2,R can be an alkyl group which collectively with R can form an alkylenebridge on the molecule; and W represents the nonmetallic atoms requiredto complete a basic heterocyclic nucleus generally having to 6 atoms inthe heterocyclic ring such as carbon, sulfur, selenium, oxygen andnitrogen to form such moieties as those selected from the groupconsisting of those of the thiazole series (e.g., thiazole,4-methylthiazole, S-methylthiazole, 4-phenylthiazole, 5-phenylthiazole,4,5-dimethylthiaz0le, 4,5-diphenylthiazole, 4-(2-thienyl)thiazole, etc.)those of the benzothiazole series (e.g., benzothiazole,4-chlorobenzothiazole, S-chlorobenzothiazole, 6-chlorobenzothiazole, 7-chlorobenzothiazole, 4-methylbenzothiazole, S-methylbenzotbiazole,6-methylbenzothiazole, S-bromobenzothiazole, -bromobenzothiazole,4-phenylbenzothiazole, S-phenylbenzothiazole, 4-methoxybenzothiazole,S-methoxybenzothiazole, 6-methoxybenzothiazole, S-iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, S-ethoxybenzothiazole,tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole,5,6-dioXymethylenebenzothiazole, S-hydroxybenzothiazole,6-hydroxybenzothiazole, etc.), those of the naphthothiazole series(e.g., a-naphthothiazole, fl-naphthothiazole,5-methoxy-B-naphthothiazole, 5-ethoxy-,8- naphthothiazole,7-methoxy-a-naphthothiazole, 8 rnethoxy a-naphthothiazole, etc.), thoseof the thianaphtheno-7',6,4,5-thiazole series (e.g.,4'-methoxythianaphtheno-7,6',4,S-thiazole, etc.), those of the oxazoleseries (e.g., 4-methyloxazole, S-methyloxazole, 4-phenyloxazole,

4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole,S-phenyloxazole, etc.), those of the benzoxazole series (e.g.,benzoxazole, S-chlorobenzoxazole, S-phenylbenzoxazole,S-methylbenzoxazole, 6-rnethylbenzoxazole, 5,6- dimethylbenzoxazole,4,6-dimethylbenzoxazole, 5 methoxybenzoxazole, 6-rnethoxybenzoxazole,S-ethoxybenzoxazole, -chlorobenzoxazole, S-hydroxybenzoxazole, 6-hydroxybenzoxazole, etc.), those of the naphthoxazole series (e.g.,a-naphthoxazole, B-naphthoxazole, etc.), those of the selenazole series(e.g., 4-methylselenazole, 4- phenylselenazole, etc.), those of thebenzoselenazole series (e.g., benzoselenazole, 5-chlorobenzoselenazole,S-rnethoxybenzoselenazole, S-hydroxybenzoselenazole,tetrahydrobenzoselenazole, etc.), those of the naphthoselenazole series(e.g., u-naphthoselenazole, ,B-naphthoselenazole, etc.) those of thethiazoline series (e.g., thiazoline, 4-rnethylthiazoline, etc.), thoseof the 2-quinoline series (e.g., quinoline, 3-methylquinoline,S-methylquinoline, 7- methylquinoline, S-methylquinoline,6-chloroquinoline, 8- chloroquinoline, 6-methoxyquinoline,6-ethoxyquinoline, 6-hydroxyquinoline, 8-hydroxyquinoline, etc.), thoseof the 4-quinoline series (e.g., quinoline, 6-methoxyquinoline,7-methylquinoline, 8-rnethylquinoline, etc.), those of thel-isoquinoline series (e.g., isoquinoline, 3,4-dihydroisoquinoline,etc.), those of the 3,3-dialkylindolenine series (e.g.,3,3-dimethylindo1enine, 3,3,5-trimethylindolcnine,3,3,7-trimethylindolenine, etc.), those of the 2-pyridine series (e.g.,pyridine, 3-methylpyridine, 4-methylpyridine, S-methylpyridine,6-methylpyridine, 3,4-dimethylpyridine, 3,5-dirnethylpyridinc,3,6-dimethylpyridine, 4,5-dirnethylpyridine, 4,6-dimethylpyridine,4-chloropyridine, S-chloropyridine, 6-chloropyridine, 3-hydroxypyridine,4-hydroxypyridine, S-hydroxypyridine, G-hydroxypyridine,3-phenylpyridine, 4-phenylpyridine, 6-phenylpyridine, etc.), those ofthe 4-pyridine series (e.g., 2- methylpyridine, 3-methylpyridine,2-chloropyridine, 3- chloropyridine, 2,3-dimethylpyridine,2,5-dimethylpyridine, 2,6-dimethylpyridine, 2-hydroxypyridine,3-hydroxypyridine, etc.), those of the l-substituted imidazole series(e.g., l-ethylirnidazole, 1-ethyl-4-phenylimidazole,1,4-dimethylimidazole, 4-rnethyl-l-phenylimidazole, etc.), those of thel-substituted benzimidazole series (e.g., l-ethylbenzimidazole,l-butylbenzimidazole, l-ethyl-4,5-dichlorobenzimidazole, etc.), those ofthe l-substituted naphthimidazole series (e.g.,1-methyl-u-naphthimidazole, 1- ethyl-a-naphthaimidazole,1-butyl-B-naphthimidazole, 6- chloro-l-methyl-a-naphthimidazole, etc.),etc. The Y substituent is preferably to form a thio-hydantoin nucleus.When Y is a sulfur atom,

the heterocyclic moiety completed by the substituent W is other than athiazoline group,

when n is 1. At least one of the substituents R R or R is preferably ahigher alkyl radical or a hydrogen atom. The alkyl substituents in thedescribed dyes can be widely varied although alkyls having 1 to 18carbon atoms are more generally used, those alkyls denominated loweralkyls having 1 to 4 carbon atoms and those alkyls denominated higheralkyls having 5 to 18 and preferably 7 to 18 carbon atoms. The alkyl andaryl radicals of the described dyes can be substituted or unsubstituted.Also useful in my invention are the holopolar dyes represented byFormula I in US. Patent 2,739,964 (Reissued as 24,292).

Typical suitable merocyanine dyes used to spectrally sensitize theemulsions of the invention include:

- (3-ethyl-2-benzothiazolinylidene) ethylidene] rhodanine 5-[(3-ethyl-2-benzothiazolinylidene) ethylidene] 2-thio-2,4-oxazolidinedione 5-[ (3-ethyl-2-benzothiazolinylideneethylidene] -3- heptyll -phenyl-2-thiohydantoin 5-[1-ethylnaphtho{1,2-d}thiazolin-2-ylidene)ethylidene]-3-n-heptyll-phenyl-Z-thiohydantoin 5-[(3-ethyl-2-benzothiazolinylidene) ethylidene] -2- thiohydantoin 5- (2,3-dihydro-9,9-dimethyl-9H-pyrrolo[1,2-a1indoll-ylmethylene-3-ethylrhodanine 5- (3-ethylnaphth{2, l-d}oXazolin-2-ylidene)ethylidene] -3 -n-hepty1- l-phenyl-Z-thiohydantoin 53-ethyl-Z-benzoxazolinylidene) ethylidene] -4- thiohydantoin 3-ethyl-5-[(3-ethyl-2-benzothiazolinylidene ethylidene] -2-thiohydantoin 5- [di3-ethyl-2-benzothiazolinylidene) isopropylidene]l-methyl-2-thiobarbituric acid 5 [di 3 -ethyl-2-benzothiazolinylideneisopropylidene] 2-thio-barbituric acid 5- [4-(3-ethyl-2-benzothiazolinylidene) 2-butenylidene1-3-n-heptyl-1-phenyl-2-thiohydantoin 5-[3-ethyl-5-phenyl-4-oxazolin-2-y1idene) ethylidene] 3-heptyll-phenyl-2-thiohyclantoin l-methyl-5-[ 1,3,3 -trimethyl-Z-indolinylidene)ethylidene]-2-thiobarbituric acid 5- 3-ethyl-2-benzothiazolinylidene)-3-hepty1lphenyl-Z-thiohydantoin 3-ethyl-5-[(3-ethyl-2-benzoxazolinylidene) isopropylidene]-2-thio-2,4-oxazolidinedione 5-[ (3-ethyl-2-benzothiazolinylidene)ethylidene] -1- phenyl-Z-thiobarbituric acid 5-[(3-ethylnaphth{2,1-d}oxazolin-2-ylidene)isopropylidene]-3-heptylrhodanine 1-ethyl-5-[ l-ethylnaphtho{ 1,2-d}thiazolin-2-ylideneisopropylidene] -2-thiobarbituric acid 5-[ l-ethyl-2(1H)-quinolylidene)ethylidene1-3- lauryl-2-thio-2,4-oxazolidinedione1-methyl-5-[ (3-methyl-2-thiazolidinylidene ethylidene]-2-thioarbituricacid 5- [4- 3-methyl-2-benzoxazoliny1idene) 1,3-neopentylene-Z-butenylidene] -2thiobarbituric acid 53-ethyl-2-benzoselenazolinylidene ethylidene] -3 hep tyl-2-thiohydantoin5 3- l,2-dihydropyrrolo{2, l-d}benzothiazoly methylene]-3-heptyl-1-phenyl-2-thiohydantoin 5-[ 5 ,6-dichloro-1,3-diethyl-2-benzimidazolinylidene ethylidene] -1-ethyl-2-thiobarbituricacid 5 (3-ethy1-2-benzothiazoliny1idene ethylidene] -3heptyl-2-seleno-2,4-thiazolidinedione 5-[3-ethyl-2-benzothiazolinylidene) ethylidene1-3-heptyl-2-thio-2,4-selenazolidinedione 5-[(3-ethyl-2-benzothiazolinylidene ethylidene] -3- hep tyl-rhodanine 5(3-ethyl-Z-benzothiazolinylidene) ethylidene] -3- lauryl-rhodanine 5-[3-ethyl-2-benzoxazolinylidene ethylidene] -3- decyl-l-phenyl-2-thiohydantoin 5-[ (3-ethyl-2-benzoxazolinylidene ethylidene]lheptyl-3-phenyl-2-thiohydantoin 3-heptyl-5-( l-methylnaphtho{1,2-d}thiazolin2- ylidene -1-phenyl-2-thiohydantoin wherein Q and T arethe same substituents as the W substituent for the above-describedmerocyanine dyes,

q and m are positive integers of l or 2 and preferably 1, n is apositive integer of 0 to 2, D is an acid anion such as chloride,bromide, iodide, perchlorate, thiocyanate, acetate, methylsulfate,ethylsulfate, benzenesulfonate, toluenesulfonate or the like. R R and Rare the respective substituents as defined for the merocyanine dyes, Ris the same as the substituents for R and when m=l and n=1 or 2, R canbe an alkyl group which collectively with R can form an alkylene bridgeon the molecule.

Typical useful cyanine dyes that can be used with the alkyl amines inthe emulsions of this invention include:

3,3 -diethyl-9-methylthiacarbocyanine iodide9-ethyl-3,3'-dimethyl-4,5,4',5'-dibenzothiacarbocyanine bromide 3,3'-diethyl-9-methyl-5 ,5 -diphenyloxacarbocyanine bromide3-methyl-l-ethylthia-2-cyanine iodide 3,3,9-triethyl-5,5'-diphenyloxacarbocyanine iodide 9-ethyl-3,3 -diB-methoxyethyl -5 ,5 -diphenyloxacarbocyanine iodideAnhydro-3-ethyl-5-phenyl-1'-(4-sulfobutyl)thia- 4-carbocyanine hydroxide1'-butyl-3-ethylselena-4'-carbocyanine iodide1-butyl-3-ethyl-4-phenylthia-4-carbocyanine iodid el',3-diethyloxa-4'-cyanine iodide 1,3-diethyl-4,5-'benzothia-2-cyanineiodide l-ethyl-1'-isopropyl-2,4-cyanine perchlorate1,3-diethylthia-4'-pyridocyanine iodide l-ethyl-l,8-ethylene-2,4-cyanineiodide l-ethyl-l,3,3-trimethylindo-4'-cyanine iodide The concentrationof the dyes utilized to improve stabilization of the direct-print imageaccording to this invention can be widely varied; the concentration ofthe dye depending on the type of emulsion and according to the effectdesired. Generally, concentrations of about 10 to about 1000 mg. of dyeper mole of silver halide are utilized. About .05 to about 1 molepercent of the dye based on the silver halide in the emulsion is atypical working range.

In forming a light-developed image with a typical photographic elementcontaining an emulsion of the invention, the photographic element isinitially exposed to a relatively short duration and high intensitysource of electromagnetic radiation (e.g., at least about .1 footcandlesecond at an intensity of more than about 100 foot-candles) such as ahigh intensity light source such as are used in oscillographs describedin Heiland, U.S. Patent 2,580,427, issued Jan. 1, 1952, high intensityvisible light, x-radiation and the like, to form a latent image in theemulsion of the photographic element. Typical suitable high-intensitylight sources are mercury vapor lamps that have high blue andultraviolet emission, xenon lamps that emit light of wavelengths similarto daylight, and tungsten lamps that have high red light emission.Thereafter the resulting latent image is photodeveloped by over-allexposure of the emulsion to a radiation source (e.g., at least about.0001 foot-candle second) of lower intensity than the original exposure,such as to a conventional fluorescent light, light from incandescentlamps commonly used for general illumination, or even ordinary daylight.Generally, the latent image formed in the emulsion in the first instanceis not visible and does not become visible until photodevelopment. Heatis desirably utilized during the photodevelopment step. Typically thesubject emulsions are heated to a temperature of about C. to 200 C. forabout 1 to 30 seconds and photodeveloped after the initial highintensity exposure.

If desired, photographic elements containing the emulsions of theinvention can be permanized by developing and fixing in aqueous chemicaldeveloping-out and fixing solutions after the initial exposure formingthe latent image, or after the above-described photodevelopment, to makearchival-quality records. Developing agents can A Density (D minus DTriethylamine (g. /mole of silver halide):

None

Example A cyanine dye, an amine stabilizer and a nitrogen-containinghalogen acceptor utilized in a silver halide emulsion provide improvedimage discrimination.

A silver chlorobr-omide emulsion is prepared by the procedure ofExample 1. A sample containing 1.36 moles of silver is mixed with 1360ml. of an aqueous solution containing 54.4 gr. of urazole, 71.5 ml. ofdiethylaminoethanol, and 73.5 ml. of 2N H 50 A sample of this solutioncontaining .0825 mole of silver is mixed with 1.4 mg. ofl-phenyl-5-mercaptotetrazole, 33.5 mg. of4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene, 14 ml. of a solutioncontaining 1 mg. of 3,3-dimethyl-9-methylthiocarbocyanine bromide and 5ml. of 5% glutaraldehyde.

The composition was coated and tested as in Example 1. The resultsshowed that the emulsion containing the diethylaminoethanol and thecyanine dye gave a better ratio of image density to background densityin the directprint system.

Samples prepared as above except containing cyanine dyes: 5,5 dichloro3,3',9 triethylthiacarbocyanine bromide; anhydro 5,5 dichloro 9 ethyl3,3 di(4- sulfoethyl)thiacarbocyanine hydroxide; and anhydro-5,5-dichloro 3,9 diethyl 3' (sulfobutyl) thiacarbocyanine hydroxide alsoshow appreciable improvements in the ratio of image density tobackground density.

The invention has been described with reference to certain embodimentsthereof for purposes of comparison of the compositions of the invention,but it will be understood that variations and modifications of theinvention can be made within the scope of the following claims.

I claim:

1. A photographic light developable, direct-print, silver halideemulsion comprising a gelatin and at least one other nitrogen-containingcompound which is a halogen acceptor and an amine stabilizer having theformula:

wherein R is an alkylene radical, R R R and R can each be a hydrogenatom, an hydroxy radical, an alkyl radical, an aryl radical, a carboxyradical, an hydroxyalkyl radical or a carboxyalkyl radical, providedthat at least one of R R R and R in said stabilizer is an alkyl radical,a carboxyalkyl radical or an hydroxyalkyl radical; m is an integer of 1to 2, X is an anion and A is the number of atoms required to form 5- or6-member saturated heterocyclic ring.

2. A photographic light developable, direct-print, silver halideemulsion comprising (1) a halogen acceptor having the formula:

R"NNHC=E Z- wherein R", R", R R R R R R R and R can each be hydrogenatoms, alkyl radicals, aryl radicals X ia radicals,wherein R is ahydrogen atom, an alkyl radical or an aryl radical; X can be oxygen orsulfur, R and R can also be wherein R is an alkylene radical, R R R andR can each be a hydrogen atom, an hydroxy radical, an alkyl radical, anaryl radical, a carboxy radical, an hydroxyalkyl radical or acarboxylkyl radical, provided that at least one of R R R or R in saidstabilizer is an alkyl radical, a carboxyalkyl radical or anhydroxyalkyl radical; m is an integer of 1 to 2, X is an anion and A isthe number of atoms required to form a 5- or 6-member saturatedheterocyclic ring.

3. A photographic, direct-print, silver halide emulsion according toclaim 1 comprising (1) a gelatin, (2) at least one othernitrogen-containing compound which is a halogen acceptor and (3) aquaternized organic amine compound as a stabilizer.

4. An emulsion according to claim 2 wherein said halogen acceptor is aurazole compound having the formula:

wherein R R and R can each be a hydrogen atom, an alkyl radical, an arylradical or a radical wherein R is a hydrogen atom, an alkyl radical oran aryl radical; X can be oxygen or sulfur; E can be an oxygen atom, asulfur atom, a selenium atom or a =NR radical, wherein R can be ahydrogen atom, an alkyl radical, an aryl radical or a 1 5 radical and Qand Z are the necessary atoms to complete a heterocyclic ring having 5or 6 members.

5. An emulsion according to claim 1 further including a glutaraldehydegelatin hardener.

6. An emulsion according to claim 1 further including an oxy plant gumgelatin hardener.

7. An emulsion according to claim 1 wherein said silver halide emulsioncomprises silver halide grains precipitated in the presence of leadions.

8. An emulsion according to claim 1 wherein said silver halide emulsioncomprises silver chlorobromide grains having a predominant amount ofradiation sensitivity internal to said grains.

9. An emulsion according to claim 1 wherein said alkyl amine isdiethyla'minoethanol, said nitrogen-containing halogen acceptor isurazole and said silver halide emulsion comprises silver chlorobromidegrains having a predominant amount of radiation sensitivity internal tosaid grains.

10. An emulsion according to claim 1 wherein the silver halide emulsioncomprises silver halide grains precipitated in the presence of athioether.

11. An emulsion according to claim 1 wherein said amine stabilizer hasthe formula:

12. An emulsion according to claim 1 wherein the amine stabilizer hasthe formula:

mamarx n-i 13. An emulsion according to claim 1 wherein the aminestabilizer has the formula:

14. A photographic, direct-print silver halide emulsion according toclaim 1 which comprises a cyanine or merocyanine dye.

15. An emulsion according to claim 14 wherein said dye is 5 (2,3dihydro-9,9-dimethyl-9H-pyrrolo-[1,2-a] -indol- 1-ylmethylene)-3-ethylrhodanine,

5 [1 18 carb0Xyethyl-4(1H)-pyridylidene]-3-ethyl rhodanine,

3-ethy1-5-[ 1-ethyl-4(H -pyridylidene] -rhodanine or3,3'-dimethyl-9-methylthiocarbocyanine bromide.

16. An emulsion according to claim 2 wherein said amine stabilizer isdiethylaminoethanol.

17. An emulsion according to claim 2 wherein said amine stabilizer istriethylamine.

18. An emulsion according to claim 2 wherein said a-mine stabilizer istetraethylammonium hydroxide.

19. An emulsion according to claim 2 wherein said amine stabilizer is amorpholine compound.

20. In a method for stabilizing the image characteristics of alight-developable, direct-print emulsion containing a gelatin and atleast One nitrogen-containing compound which is a halogen acceptor, theimprovement which comprises the addition during the preparation of theemulsion of an amine stabilizer having the formula:

wherein R is an alkylene radical, R R R and R each can be a hydrogenatom, an hydroxy radical, an alkyl radicl, an aryl radical, a carboxyradical, an hydroxyalkyl radical or a carboxyalkyl radical, providedthat at least one of R R R or R in said stabilizer is an alkyl radical,a carboxyalkyl radical or an hydroxyalkyl radical; m: is an integer of lto 2, X is an anion and A is the number of atoms required to form a 5-or 6-member saturated heterocyclic ring.

21. In a method for stabilizing the image characteristics of alight-developable, direct-print emulsion containing a gelatin and atleast one nitrogen-containing compound which is a halogen acceptor, theimprovement which comprises the addition during the preparation of theemulsion of a cyanine or merocyanine dye in combination with an aminestabilizer having the formula:

wherein R is an alkylene radical, R R R and R each can be a hydrogenatom, an hydroxy radical, an alkyl radical, an aryl radical, a carboxyradical, an hydroxy alkyl radical or a carboxyalkyl radical, providedthat at least one of R R R or R in said stabilizer is an alkyl radical,a carboxyalkyl radical or an hydroxyalkyl radical, m is an integer of lto 2, X is an anion and A is the number of atoms required to form a 5-or 6-member saturated hetcrocyclic ring.

References Cited UNITED STATES PATENTS 3,017,271 1/1962 Piper 96l09 XR3,128,183 4/1964 Jones et al. 96-107 3,271,157 9/1966 McBride 961073,367,780 2/1968 Fix et al 96109 XR NORMAN G. TORCHIN, Primary ExaminerR. E. FIGHTER, Assistant Examiner US. Cl. X.R. 96-107, 109

STATES PATENT OFFICE 0F CORRECTION Patent Dated December 30. 1969Inventofls) Karl son It is error appears in the above-identified patentand that eaidLett ere Patent are hereby corrected as shown below:

"improvemnt" should read improvement- Column 3;, :lineffl before"triazolethiol", should be inserted thfiwo era Column 5, line 71, after"derivatives", should be nserted Column 8, lines L B-n6, "1ethyl-fl-naphthainiidatole" should read 1 -ethyl- [-naphthimidazoleColman 9",fline 145, that portion of formula reading"-2-thioarbiturio"should read 2-thiobarbiturio line 50, that portionofyformulareading "benzothiazoly)" should read benzothiazolylJfl Column1 2, line 5, "backgronud" should read baokgroundy- Column 1L lines 1-5,Formula B set forth as should read 1 Column 114., line "L 5,ll'oarboxylkyl" should read carboxyalkyl Column '16,;QClaim 20, lines16-17, "radial" should read radical SIGNED AND SEALED a v JUN 1 6 1970Eamammmn.

1 mm 1:. seem Attestmg Officer I commissioner of ht;

